//The MIT License

//Copyright (c) 2009 Lluis Sanchez, Nick Darnell

//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:

//The above copyright notice and this permission notice shall be included in
//all copies or substantial portions of the Software.

//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//THE SOFTWARE.

using System;
using System.Reflection;
using System.Reflection.Emit;

namespace Polymorph
{
    /// <summary>
    /// The <see cref="CodeNew"/> represents a new operation on a specific object type.
    /// </summary>
    public class CodeNew : CodeExpression
    {
        private Type m_type;
        private ConstructorInfo m_ctor;
        private CodeExpression[] m_parameters;

        /// <summary>
        /// Initializes a new instance of the new operation expression.
        /// </summary>
        /// <param name="type">The type being created.</param>
        /// <param name="parameters">The different expressions to pass to the constructor.</param>
        public CodeNew(Type type, params CodeExpression[] parameters)
        {
            m_type = type;
            Type[] ptypes = new Type[parameters.Length];

            for (int n = 0; n < parameters.Length; n++)
                ptypes[n] = parameters[n].ResultType;

            m_ctor = type.GetConstructor(
                BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, 
                null, ptypes, null);

            if (m_ctor == null)
                throw new InvalidOperationException("Constructor not found");

            m_parameters = parameters;
        }

        /// <summary>
        /// Generates the IL for the new operation.
        /// </summary>
        /// <param name="gen">The IL generator to use.</param>
        public override void Generate(ILGenerator gen)
        {
            foreach (CodeExpression exp in m_parameters)
                exp.Generate(gen);
            gen.Emit(OpCodes.Newobj, m_ctor);
        }

        /// <summary>
        /// Prints the code in a human readable form.
        /// </summary>
        /// <param name="cw">The code writer to use.</param>
        public override void PrintCode(CodeWriter cw)
        {
            cw.Write("new " + m_type.Name + "(");
            for (int n = 0; n < m_parameters.Length; n++)
            {
                if (n > 0) cw.Write(", ");
                m_parameters[n].PrintCode(cw);
            }
            cw.Write(")");
        }

        /// <summary>
        /// Gets the resulting type of the new object being created.
        /// </summary>
        public override Type ResultType
        {
            get { return m_type; }
        }
    }
}